1. Field of the Invention
The present invention relates to a copying machine, and more particularly, to a copying machine employing an ink donor sheet for recording desired data on a recording sheet of paper.
2. Description of the Prior Art
Conventional copying machines utilize diazo photography or xerography.
Copying machines which operate on the principle of diazo photography employ a photosensitive sheet of paper that is superposed on an original to be copied and exposed to produce a recorded image. A disadvantage of such copying machines is that only one copy can be made from a single original in one copying operation. Therefore, it is extremely troublesome to produce a number of copies of one original. Another problem is that only transparent or semitransparent originals can be copied.
Xerographic copying machines include an electrostatic recording drum or sheet for producing an electrostatic latent image thereon, which is developed with toner into a toner image. The toner image is then transferred and thermally fixed to a recording sheet to produce a recorded image. The xerographic copying machine can produce a number of copies in one operation by subjecting the original to repeated exposure, and suffers from no limitation on the types of originals that can be copied. However, a drawback of the xerographic copying machine is that a large amount of electric power is consumed in fixing a toner image to a recording sheet. In addition, because the fixing unit emits a large quantity of heat, the copying machine requires a heat shielding mechanism and an exhaust mechanism for protecting circuit components from the heat discharged from the fixing unit. Therefore, the copying machine is large and expensive to manufacture.
The xerographic copying process which utilizes static electricity in forming latent images also has the disadvantage of being sensitive to its environment. It may fail to transfer an image properly when the recording sheet is dampened due to high humidity.